The present invention relates generally to multifocal ophthalmic lenses, and more particularly, to trifocal ophthalmic lenses, such as trifocal intraocular lenses (IOLs).
A plurality of ophthalmic lenses are available for correcting visual disorders, such as cataract, myopia, hyperopia or astigmatism. For example, an intraocular lens (IOL) can be implanted in a patient's eye during cataract surgery to compensate for the lost optical power of the removed natural lens. Though providing the requisite optical power, IOLs do not provide the accommodation (i.e., the ability to focus on objects at varying distances) that can be attained by a natural lens. However, multi-focal IOLs are known that can provide a certain degree of accommodation (also known as pseudo-accommodation). For example, bifocal diffractive IOLs are available that are capable of providing a near and a far focus.
Trifocal ophthalmic lenses are also known for providing a near and a far focus, as well as an intermediate focus. Such conventional trifocal lenses, however, suffer from a number of shortcomings. For example, they provide intermediate vision at the expense of degradation of the far and/or near vision.
Accordingly, there is a need for enhanced multifocal ophthalmic lenses, and particularly, trifocal ophthalmic lenses. There is also a need for such multifocal lenses in the form of intraocular lenses (IOLs) that can be implanted in patients' eyes, e.g., to replace the natural lens.